Abstract The preparation of silicon carbide films at substrate temperatures lower than 600 °C and deposition rates greater than 0.2 μm h -1 was studied. A new process (the plasma deposition process) in which all the reactant species were supplied by pure gases was investigated. In this process the gas pressure is of the order of 10 -3 Torr and the deposition rate is independent of the substrate temperature and the cathode potential and can be controlled by the gas throughput and the r.f. power. For a high r.f. input power the chemical composition of the SiC films is equal to the mixing ratio of the reactant gases. The films prepared were found to be amorphous and silicon carbide like by reflection high energy electron diffraction and IR transmission spectroscopy analyses. Properties of the films such as transparency, adhesion, hardness and corrosion resistance are improved with both increasing r.f. power and increasing cathode potential. The SiC films are transparent and show high hardnesses, excellent corrosion resistance and excellent adhesion to both silicon substrates and fused quartz substrates. A large compressive film stress ranging from 2 × 10 8 to 5 × 10 9 dyn cm -2 was found.